Wis. Stat. § 807.05
No agreement, stipulation, or consent between the parties or their attorneys, in respect to the proceedings in an action or special proceeding shall be binding unless made in court or during a proceeding conducted under s. 807.13 or 967.08 and entered in the minutes or recorded by the reporter, or made in writing and subscribed by the party to be bound thereby or the party's attorney.
Wis. Stat. § 807.05
When a stipulation did not satisfy this section, summary judgment was improper because there was no factual basis on the record for the decision. Wilharms v. Wilharms, 93 Wis. 2d 671, 287 N.W.2d 779 (1980). An oral agreement to settle an action that does not comply with this section is unenforceable. Adelmeyer v. Wisconsin Electric Power Co. 135 Wis. 2d 367, 400 N.W.2d 473 (Ct. App. 1986). This section does not affect procedural stipulations or judicial admissions that dispense with evidentiary requirements. State v. Aldazabal, 146 Wis. 2d 267, 430 N.W.2d 614 (Ct. App. 1988). The subscription requirement is met by a stamped facsimile signature. This provision does not require hand-written signatures. Kocinski v. Home Insurance Co. 154 Wis. 2d 56, 452 N.W.2d 360 (1990). Contract law is not binding in construing, enforcing, or modifying stipulations, but principles of contract law, including the uniform commercial code, may illuminate a stipulation dispute, even to the point of being dispositive. Phone Partners Ltd. v. C. F. Communications, 196 Wis. 2d 702, 512 N.W.2d 155 (Ct. App. 1995), 94-2279. To constitute a stipulation under this section, a statement must be conclusive on the question. The concession of a fact to the court made for strategic reasons and not agreed to by the other party is not a stipulation and the court need not engage in a colloquy with the parties about it. Fritz v. Fritz, 231 Wis. 2d 33, 605 N.W.2d 270 (Ct. App. 1999), 98-0605. This section does not provide for a party to subscribe to an agreement through general conduct. A party's assent or approval must be formalized in some way on the document itself. Laska v. Laska, 2002 WI App 132, 255 Wis. 2d 823, 646 N.W.2d 393, 02-0022. A fax transmittal letter sent by counsel that bore counsel's initials at the conclusion of the message text was subscribed within the meaning of this section thereby rendering the settlement terms accepted in that letter binding on the client and enforceable by the court. Waite v. Easton-White Creek Lions, Inc. 2006 WI App 19, 289 Wis. 2d 100, 709 N.W.2d 88, 05-1688. When an attorney signed a settlement agreement contingent on his client's consent by noon the following day and the client did not consent to the settlement by the deadline created by the contingency, the settlement was not enforceable under this section. Subsequent actions by the parties cannot fulfill the statutory requirements. Neither the untimely oral assurances by the attorney to the other parties, nor the attorney's call notifying the court that a settlement had been reached, satisfied the contingency set forth in the agreement. Affordable Erecting, Inc. v. Neosho Trompler, Inc. 2006 WI 67, 291 Wis. 2d 259, 715 N.W.2d 620, 04-2746. Oral settlements are not invariably unenforceable. Gliniciki v. Borden, Inc. 444 F. Supp. 619.